How can Borg destroy Guinan's civilisation? [duplicate]

This question already has an answer here:

• What are Guinan's powers from Star Trek: TNG? 5 answers

How is it possible that the Borg destroyed the entire El-Aurian civilisation (i.e. Guinan's), if we know from the "Q Who" episode, that even Q itself is wary of Guinan (or at least doesn't like her too much, and sees her as a serious opponent, which doesn't happen to often in case of Q)?

If Q is "scared" of Guinan, then this suggests, that (at least in some areas) Guinan is more powerful than Q. If that's true, then how can she and her people be raided by the Borg and eventually destroyed?

What is the correct point of view on this matter?

For reference, Q's comments about Guinan in "Q Who?":

GUINAN: I knew it was you.

Q: You! Picard, if you had half the sense you pretend to have, you would get her off your ship immediately. And if you like, I'd be more than pleased to expedite her departure.

PICARD: You know him?

GUINAN: We have had some dealings.

Q: Those dealings were two centuries ago. This creature is not what she appears to be. She's an imp, and where she goes, trouble always follows.